<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

defined('THINK_PATH') or exit();
/**
 * Memcache缓存驱动
 * @category   Extend
 * @package  Extend
 * @subpackage  Driver.Cache
 * @author    liu21st <liu21st@gmail.com>
 */
class CacheMemcache extends Cache {

	/**
	 * 架构函数
	 * @param array $options 缓存参数
	 * @access public
	 */
	function __construct($options=array()) {
		//[sae] 下不用判断memcache是否存在
		// if ( !extension_loaded('memcache') ) {
		//     throw_exception(L('_NOT_SUPPERT_').':memcache');
		// }
		if(empty($options)) {
			$options = array (
                'host'        =>  C('MEMCACHE_HOST') ? C('MEMCACHE_HOST') : '127.0.0.1',
                'port'        =>  C('MEMCACHE_PORT') ? C('MEMCACHE_PORT') : 11211,
                'timeout'     =>  C('DATA_CACHE_TIMEOUT') ? C('DATA_CACHE_TIMEOUT') : false,
                'persistent'  =>  false,
			);
		}
		$this->options      =   $options;
		$this->options['expire'] =  isset($options['expire'])?  $options['expire']  :   C('DATA_CACHE_TIME');
		$this->options['prefix'] =  isset($options['prefix'])?  $options['prefix']  :   C('DATA_CACHE_PREFIX');
		$this->options['length'] =  isset($options['length'])?  $options['length']  :   0;
		//  $func               =   isset($options['persistent']) ? 'pconnect' : 'connect';
		$this->handler      =  memcache_init();//[sae] 下实例化
		//[sae] 下不用链接
		$this->connected=true;
		// $this->connected    =   $options['timeout'] === false ?
		//     $this->handler->$func($options['host'], $options['port']) :
		//     $this->handler->$func($options['host'], $options['port'], $options['timeout']);
	}

	/**
	 * 是否连接
	 * @access private
	 * @return boolen
	 */
	private function isConnected() {
		return $this->connected;
	}

	/**
	 * 读取缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @return mixed
	 */
	public function get($name) {
		N('cache_read',1);
		return $this->handler->get($_SERVER['HTTP_APPVERSION'].'/'.$this->options['prefix'].$name);
	}

	/**
	 * 写入缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @param mixed $value  存储数据
	 * @param integer $expire  有效时间（秒）
	 * @return boolen
	 */
	public function set($name, $value, $expire = null) {
		N('cache_write',1);
		if(is_null($expire)) {
			$expire  =  $this->options['expire'];
		}
		$name   =   $this->options['prefix'].$name;
		if($this->handler->set($_SERVER['HTTP_APPVERSION'].'/'.$name, $value, 0, $expire)) {
			if($this->options['length']>0) {
				// 记录缓存队列
				$this->queue($name);
			}
			return true;
		}
		return false;
	}

	/**
	 * 删除缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @return boolen
	 */
	public function rm($name, $ttl = false) {
		$name   =   $_SERVER['HTTP_APPVERSION'].'/'.$this->options['prefix'].$name;
		return $ttl === false ?
		$this->handler->delete($name) :
		$this->handler->delete($name, $ttl);
	}

	/**
	 * 清除缓存
	 * @access public
	 * @return boolen
	 */
	public function clear() {
		return $this->handler->flush();
	}

	/**
	 * 队列缓存
	 * @access protected
	 * @param string $key 队列名
	 * @return mixed
	 */
	//[sae] 下重写queque队列缓存方法
	protected function queue($key) {
		$queue_name=isset($this->options['queue_name'])?$this->options['queue_name']:'think_queue';
		$value  =  F($queue_name);
		if(!$value) {
			$value   =  array();
		}
		// 进列
		if(false===array_search($key, $value)) array_push($value,$key);
		if(count($value) > $this->options['length']) {
			// 出列
			$key =  array_shift($value);
			// 删除缓存
			$this->rm($key);
			if (APP_DEBUG) {
				//调试模式下记录出队次数
				$counter = Think::instance('SaeCounter');
				if ($counter->exists($queue_name.'_out_times'))
				$counter->incr($queue_name.'_out_times');
				else
				$counter->create($queue_name.'_out_times', 1);
			}
		}
		return F($queue_name,$value);
	}

}